JPH06235067A - Formation of silicon oxide film - Google Patents

Abstract

PURPOSE:To provide the ceramic type silicon oxide film which is a thick film, is flat, is free from cracks and pinholes and is insoluble in an org. solvent by heating a base material on which a film mainly consisting of the silicon base resin expressed by specific general formula is formed. CONSTITUTION:The film mainly consisting of the silicon base resin expressed by the general formula: (HR2SiO1/2)x(SiO4/2)1.0 is formed on the surface of the base material. In the formula, R is H, alkyl, aryl; X is 0.1<=X<=2.0. This base material is then heated to convert the film to the ceramic type silicon oxide film. The desired film which is flattened in >=1mu level difference and does not contain silanol groups and alkoxy groups to be the cause for moisture absorption and carbon poison in the formed silicon oxide is formed at the temp. much lower than the m.p. of Al by this method. A tendency to high polymn. is admitted during preservation in a gelatinized or molten state at the time of synthesis if X in the formula is below the lower limit. On the other hand, the sufficient film hardness is not obtainable if X is above the upper limit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a silicon oxide film on the surface of a substrate, and more specifically, it is a ceramic film insoluble in organic solvents, which is a thick film on the surface of the substrate and has neither cracks nor pinholes. The present invention relates to a method for forming a silicon oxide film.

[0002]

2. Description of the Related Art Generally, in order to protect the surface of a base material, a protective film is formed on the surface of the base material. In particular, in the electric and electronic industries, with the recent high integration and multi-layering of semiconductor devices, the complexity of semiconductor devices and the unevenness of the surface of the semiconductor device have become remarkable. Protection against static, electrostatic, ionic, non-ionic and radiation pollution,
And for the purpose of flattening the unevenness of the semiconductor device surface,
On the surface of a semiconductor device, a passivation film or an interlayer insulating film for the purpose of insulating and flattening between wirings is formed as a circuit is multi-layered.

A silicon oxide film is generally used as a passivation film and an interlayer insulating film formed on the surface of a semiconductor device. Examples of methods for forming a silicon oxide film on the surface of a semiconductor device include a CVD (Chemical Vapor Deposition) method and a spin coating method. Examples of methods for forming a silicon oxide film on the surface of a semiconductor device by a spin coating method include: Inorganic SOG (spin on glass) and organic SOG are available.

However, since a silicon oxide film formed of inorganic SOG has cracks when its thickness exceeds 0.3 μm, multiple coatings are required to fill the steps of a device substrate having irregularities of 1 μm or more. And, in particular,
Since the flattening ability of the film itself is poor, a flattening step by etching back was necessary after the film formation.

On the other hand, a silicon oxide film formed of an organic SOG can form a film having a crack of 1 μm or more with one coating, but like the inorganic SOG, the flattening ability of the film itself is obtained. However, a flattening process by etching back was necessary after the film formation. In addition, since a large amount of silanol groups and alkoxy groups remain in the silicon oxide film, the hygroscopicity is high, and a problem of carbon poison (carbon contamination) due to the residual alkoxy groups occurs during oxygen plasma treatment, which causes a problem as an interlayer insulating agent. There was a problem of poor electrical reliability.

Therefore, a method of forming a silicon oxide film by hydrogen silsesquioxane has been proposed as a method for improving the problems of the silicon oxide film formed by the inorganic SOG and the organic SOG (Japanese Patent Laid-Open No. 3-30083). 18367
(See Japanese Patent Publication No. 5). This method is excellent in the ability to flatten the steps by heating and melting the resin itself,
No etch back process is required. Further, since it does not have an organic group in its structural unit, it has an advantage that there is no fear of carbon poison during oxygen plasma treatment.

However, in the method of forming a silicon oxide film proposed by Japanese Patent Laid-Open No. 183675 / 0.8, 0.8 μm
Since it is not possible to form a silicon oxide film having a film thickness of (8000 angstroms) or more, the unevenness of the semiconductor device surface, that is, the unevenness of the semiconductor device surface having a step of 0.8 μm (8000 angstroms) or more is completely removed. There was a problem that it could not be flattened. Further, when a thick silicon oxide film is to be obtained by this method, cracks and pinholes may occur in the silicon oxide film, resulting in a problem that the reliability of the semiconductor device is significantly reduced.

[0008]

DISCLOSURE OF THE INVENTION The inventors of the present invention have formed a silicon oxide thick film having a level difference of 1 μm or more by heating and melting to form a silicon oxide thick film free from cracks and pinholes, and formed in the formed silicon oxide. Further, the inventors have earnestly studied a method of forming a silicon oxide film insoluble in an organic solvent, which does not have a silanol group and an alkoxy group which cause moisture absorption and carbon poison, and finally arrived at the present invention.

That is, an object of the present invention is to provide a method for forming a ceramic-like silicon oxide film insoluble in an organic solvent, which is a thick film on the surface of a substrate and has neither cracks nor pinholes.

[0010]

_{MEANS FOR SOLVING THE} PROBLEMS AND ACTION THEREOF The present invention provides a substrate of the general formula: (HR ₂ SiO _1/2 ) _X (SiO _4/2 ) _1.0 (wherein R is a hydrogen atom or an alkyl group). Is a group selected from the group consisting of a group and an aryl group, and X is 0.1 ≦ X ≦
It is 2.0. Forming a coating film comprising a silicon resin as a main component, and then heating the substrate having the coating film formed thereon to form a ceramic silicon oxide film. Regarding the method.

The method for forming the silicon oxide film of the present invention will be described in detail.

In the present invention, the coating film on the surface of the base material is mainly composed of a silicon resin represented by the general formula: (HR ₂ SiO _1/2 ) _X (SiO _4/2 ) _1.0 . In the above formula, R is a group selected from the group consisting of a hydrogen atom, an alkyl group and an aryl group, and specific examples of the alkyl group of R include a methyl group, an ethyl group, a propyl group and a butyl group, As the aryl group of R, a phenyl group, a tolyl group,
A xylyl group is exemplified, and R is preferably a methyl group or a phenyl group. Further, in the above formula, X is 0.1 ≦ X ≦
2.0, preferably 0.3 ≦ X ≦ 1.0.
This is because when X is less than 0.1, the silicon resin tends to gel during the synthesis, and even if the silicon resin does not gel during the synthesis, the resin itself tends to have a high molecular weight during storage in the solution state. When X exceeds 2.0, sufficient hardness of the silicon oxide film cannot be obtained, or the content of organic groups in the silicon resin becomes relatively large. This is because sufficient etching resistance cannot be obtained in the oxygen plasma treatment process.

The molecular weight of such a silicon resin is not particularly limited, but in order to exhibit the characteristic that the resin melts and flows during heating to flatten the steps of the semiconductor device substrate, the weight average molecular weight is preferably. 100,
000 or less, and the physical properties such as viscosity and softening point are not particularly limited, but the softening point is preferably 400 ° C. or less.

The method for producing such a silicon resin is not particularly limited. For example, pure water is dissolved in alcohol, and a mixed solution of tetraalkoxysilane and dimethylmonochlorosilane is dropped into the solution. Examples include a method of synthesizing the silicon resin and a method of dissolving 1,1,3,3-tetramethyldisiloxane in a cosolvent of alcohol and hydrochloric acid and dropping tetraalkoxysilane to the solution to form the silicon resin. .

In the present invention, the coating film on the surface of the base material contains the above-mentioned silicon resin as a main agent, but other components are not particularly limited, but specifically, as other components,
Platinum compounds such as chloroplatinic acid, platinum-alkene complexes, platinum-vinylsiloxane complexes, chloroplatinic acid alcohol solutions; acidic catalysts such as hydrochloric acid and acetic acid; alcohols such as methanol and ethanol; and terminal silanols. Examples of the low molecular weight siloxane have.

In the present invention, the method of forming a coating film containing the above-mentioned silicon resin as the main component on the surface of the substrate is not particularly limited. Specifically, as this method, the liquid silicon resin or the silicon resin in an organic solvent is used. Spin coating or spraying of the dissolved solution, or dipping the base material into the silicon resin or the solution, and then removing the solvent if necessary, forms a film composed mainly of silicon resin on the base material surface. Or a method in which the silicon resin which is solid at room temperature is heated and softened on the base material to form a coating film containing the silicon resin as a main component on the surface of the base material. In the former method, the organic solvent used to dissolve the silicon resin is not particularly limited as long as it can uniformly dissolve the silicon resin, but as such an organic solvent, specifically, methanol, Alcohol solvents such as ethanol; Cellosolve solvents such as methyl cellosolve and ethyl cellosolve; Ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; Butyl acetate, isoamyl acetate,
Ester solvents such as methyl cellosolve acetate and ethyl cellosolve acetate; chain siloxanes such as 1,1,1,3,3,3-hexamethyldisiloxane and 1,1,3,3-tetramethyldisiloxane, 1, 1, 3, 3,
Examples include cyclic solvents such as 5,5,7,7-octamethyltetracyclosiloxane and 1,3,5,7-tetramethyltetracyclosiloxane, and silicone solvents such as silane compounds such as tetramethylsilane and dimethyldiethylsilane. Further, two or more of the above organic solvents can be used in combination.

In the present invention, the base material for forming the coating film containing the above-mentioned silicon resin as a main component is not particularly limited. Specific examples of such a base material include a glass base material,
Examples include ceramic base materials, metal base materials, and semiconductor devices, with semiconductor devices being particularly preferred. Such a semiconductor device may have irregularities on the surface, and the method for forming a silicon oxide film of the present invention can flatten the irregularities on the surface of such a semiconductor device.

Next, the ceramic-like silicon oxide film can be formed by heating the base material on which a coating film containing silicon resin as a main component is formed. Further, in the present invention, the temperature and the heating time for heating the base material having the coating formed of the silicon resin as the main agent are not particularly limited, but preferably the conditions in which the coating formed of the silicon resin as the main agent is insoluble in a solvent, for example, It is desirable to heat at a temperature of 100 ° C. or higher for 30 minutes or longer, and more preferably under conditions where SiH groups, silanol groups and alkoxy groups hardly remain in the formed silicon oxide film, for example, at a temperature of 300 ° C. or higher. It is desirable to heat for 30 minutes or more.

In the method for forming a silicon oxide film of the present invention, a method for confirming whether or not the ceramic silicon oxide film can be formed is as follows. The main component is the silicon resin formed on the surface of the substrate by an infrared spectrophotometer. as becomes SiH groups in the film (910 cm ^-1 and 2150 cm ^-1
A sharp strong absorption peak derived from SiH group), an alkoxy group (a sharp weak absorption peak derived from an alkoxy group at 2870 cm ⁻¹ ) and a silanol group (35
It can be confirmed by measuring the respective contents of broad medium absorption peaks derived from silanol groups near 00 cm ⁻¹ and then measuring and comparing them in the silicon oxide film after heating. . Further, it can be confirmed by immersing the heated silicon oxide film in various organic solvents and checking whether the silicon oxide film is insoluble in the organic solvent.

According to the method for forming a silicon oxide film of the present invention, a ceramic silicon oxide film having a thickness of 1 μm or more can be formed without causing cracks and pinholes, and the content of the organic component in the silicon resin can be increased. The internal stress of the produced ceramic silicon oxide film can be relaxed by adjusting Furthermore, according to the method for forming a silicon oxide film of the present invention, since the ceramic silicon oxide film can be formed at a temperature much lower than the melting point of aluminum, the aluminum used for the circuit wiring of the semiconductor device is melted. Since it does not deteriorate, the method for forming a silicon oxide film of the present invention is useful as a method for forming a passivation film and an interlayer insulating film on a semiconductor device surface, and a substrate surface having the obtained ceramic silicon oxide film is formed. Further, since a silicon oxide film or an organic resin film can be formed, it is useful as a method for forming an interlayer insulating film of a multilayer semiconductor device.

[0021]

The present invention will be described in detail with reference to Reference Examples, Examples and Comparative Examples. The silicon resin used in the present invention was prepared by the following reference examples, but the method for synthesizing the silicon resin is not limited to the following reference examples.

[0022]

Reference Example 1 40 g of methanol and 19.0 g of water were weighed in a 200 ml-four-necked flask equipped with a dropping pipe with a straight pipe, a condensing pipe condenser, and a thermometer, and the liquid temperature was kept at 2 ° C or lower by ice cooling. It was lowered and nitrogen was passed through the system at a very small flow rate. While stirring the solution in this state, a mixture of 13.2 g (0.14 mol) of dimethylchlorosilane and 60.8 g (0.4 mol) of methyl orthosilicate was added dropwise through a dropping pipe with a straight pipe over 40 minutes. On the way, the liquid temperature was 13 due to heat generation.
However, the temperature dropped to 8 ° C at the end of the dropping.
Further, stirring was continued for 15 minutes in an ice-cooled state, and then at room temperature for 4 hours. The reaction solution was colorless and transparent. Then, 200 ml of methyl isobutyl ketone (hereinafter abbreviated as MIBK) was added to the reaction liquid, and 200 ml of water was further added, and the phases were separated into two layers. The lower layer was collected, 100 mL of MIBK was added thereto, and the mixture was shaken and then phase-separated, and the upper layer was collected and combined with the previous upper layer. When 400 ml of water was added and shaken, it became an emulsified state, so 700 ml of diethyl ether was added and allowed to stand, and the phases were separated (about 1 for phase separation).
It took 0 hours). The upper layer was collected, magnesium sulfate was added thereto, and the mixture was left for 6 hours. Thereafter, magnesium sulfate was filtered off, and the filtrate was recovered (hereinafter, this filtrate was referred to as filtrate A
Call. ). The filtrate A was weighed on an aluminum dish and the solid content weight% was measured to be 6.35%. Next, filtrate A
125 ml of it was weighed in a wide-neck bottle made of high-density polyethylene (161.07 g), and blown with nitrogen to obtain a solid content% by weight.
= Concentrated to 30.3%. At this point, no odor of diethyl ether or methanol could be detected from the concentrated liquid. A predetermined amount of MIBK was added to this concentrated solution to dilute it to a solid content weight% = 30.0% (hereinafter, this solution is referred to as solution A). Solution A was directly diluted with tetrahydrofuran to prepare a solution having a solid content weight concentration of 0.2%, and this solution was injected into gel permeation chromatography using tetrahydrofuran as a carrier solvent. 6260, the weight average molecular weight was 9890, and the dispersity was 1.58.
As a result of ²⁹ Si-nuclear magnetic resonance spectrum analysis, this dissolved component was confirmed to be a silicon resin having the following structural formula. [H (CH ₃ ) ₂ SiO _1/2 ] _0.35 (SiO _4/2 ) _1.0

Further, the solution A was dropped on a silicon wafer and left to stand in air at room temperature to dry the solvent, thereby forming a coating film having a solid content of about 1 μm. Structural analysis of this film by a transmission mode using a Fourier transform infrared spectrophotometer revealed a strong strong absorption peak due to a siloxane bond near 1100 cm ⁻¹ and a sharp strong absorption peak due to a Si—CH ₃ group at 1260 cm ^−1. Absorption peak,
910 cm ^-1 and from SiH groups 2150 cm ^-1 sharp strong absorption peaks, sharp weak absorption peak derived from the alkoxy group to 2870cm ^-1, 2960
sharp medium absorption peak derived from C-H groups in cm ^-1, absorption peaks moderate broad derived from silanol group near 3500 cm ^-1 was observed. Solution A 1
When sealed and stored at room temperature in a 25 ml wide-bottle made of high-density polyethylene, no visual change such as viscosity change was observed after one month, and the number average molecular weight was 62.
60, the weight average molecular weight was 9890, and the dispersity was 1.58.

[0024]

[Reference Example 2] 20 g of methanol and 9.5 g of water were weighed in a 200 ml-four-necked flask equipped with a dropping pipe with a straight pipe, a condenser of a spiral tube and a thermometer, and the liquid temperature was lowered to 5 ° C or lower by ice cooling. It was lowered and nitrogen was passed through the system at a very small flow rate. While stirring the solution in this state, a mixture of 18.9 g (0.20 mol) of dimethylchlorosilane and 30.4 g (0.2 mol) of methyl orthosilicate was added dropwise through a dropping pipe with a straight pipe over 40 minutes. On the way, the liquid temperature was 13 due to heat generation.
However, the temperature dropped to 8 ° C at the end of the dropping.
Further, stirring was continued for 15 minutes in an ice-cooled state, and then at room temperature for 4 hours. The reaction solution was colorless and transparent. MI in the reaction solution
When 100 ml of BK was added and 100 ml of water was further added, the phases were separated into two layers. The lower layer was collected, 50 mL of MIBK was added thereto, and the mixture was shaken and then phase-separated. The upper layer was collected and combined with the previous upper layer. Water 2
When 00 ml was added, and the mixture was shaken and then allowed to stand, layer separation occurred immediately. Further, 200 ml of water was added and the mixture was washed with water, the upper layer was collected, magnesium sulfate was added thereto, and the mixture was allowed to stand for 10 hours. After magnesium sulfate was filtered off, a part of the filtrate was taken and the solvent was completely removed by a nitrogen blow to obtain a colorless and transparent highly viscous substance. This substance was soluble in acetone and carbon tetrachloride.
When this material was left in the air for several days, its appearance changed to a white solid, but its solubility did not change. At the same time, the solid yield in the filtrate was calculated to be 25.6 g. (100% of theoretical yield). The remaining filtrate was once concentrated by nitrogen blowing to a concentration of solid content exceeding 30%, and then a predetermined amount of MIBK was added to prepare a solution having a solid content concentration of 30% (hereinafter, this solution is referred to as solution B). ). Solution B is diluted as it is with tetrahydrofuran to obtain a solid content weight concentration of 0.2.
% Solution was prepared, and this solution was injected into gel permeation chromatography using tetrahydrofuran as a carrier solvent. The number average molecular weight of the dissolved component was 4
190, weight average molecular weight 8510, dispersity 2.03
Met. As a result of ²⁹ Si-nuclear magnetic resonance spectrum analysis, this dissolved component was confirmed to be a silicon resin having the following structural formula. [H (CH ₃ ) ₂ SiO _1/2 ] _1.0 (SiO _4/2 ) _1.0

Further, the solution B was dropped on a silicon wafer and left to stand at room temperature in the air to dry the solvent, thereby forming a coating film having a solid content of about 1 μm. Structural analysis of this film by a transmission mode using a Fourier transform infrared spectrophotometer revealed a strong strong absorption peak due to a siloxane bond near 1100 cm ⁻¹ and a sharp strong absorption peak due to a Si—CH ₃ group at 1260 cm ^−1. Absorption peak,
910 cm ^-1 and from SiH groups 2150 cm ^-1 sharp strong absorption peaks, sharp weak absorption peak derived from the alkoxy group to 2870cm ^-1, 2960
sharp medium absorption peak derived from C-H groups in cm ^-1, absorption peaks moderate broad derived from silanol group near 3500 cm ^-1 was observed.

[0026]

[Reference Example 3] In a 200 ml-four-necked flask equipped with a dropping pipe with a straight pipe, a spiral condenser and a thermometer, 20 g of methanol, 12.1 g of 7.4N-hydrochloric acid (hydrogen chloride = 0.07 mol) and 1 were added. , 1,3,3-tetramethyldisiloxane 4.69 g (0.035 mol) was weighed,
The liquid temperature was lowered to 5 ° C. or lower by cooling with ice, and nitrogen was passed through the system at a very small flow rate. While stirring the solution in this state, 30.4 g of methyl orthosilicate (0.
(2 mol) was added dropwise over 40 minutes. During the process, the temperature of the liquid rose to 13 ° C due to heat generation, but it was 8
It fell to ℃. Further, stirring was continued for 15 minutes in an ice-cooled state, and then at room temperature for 4 hours. The reaction solution was colorless and transparent. When 100 ml of MIBK was added to the reaction solution and 100 ml of water was further added, phase separation into two layers was performed. The lower layer was collected, 50 mL of MIBK was added thereto, and the mixture was shaken and then phase-separated. The upper layer was collected and combined with the previous upper layer. When 200 ml of water was added and shaken, it became an emulsified state, so 200 ml of diethyl ether was added and allowed to stand, and the phases were separated (it took about 10 hours for phase separation. The upper layer was transparent, but the lower layer was It was milky and had a small amount of viscous macromolecular substance suspended.) The lower layer was removed, 200 ml of water was further added, and the mixture was shaken and allowed to stand. Phase separation occurred quickly. Collect the upper layer,
Magnesium sulfate was added to this and left for 2.5 days. After magnesium sulfate was filtered off, a part of the filtrate was taken and the solvent was completely removed by nitrogen blowing, whereby a white solid was obtained. This solid was insoluble in acetone. At the same time, the solid content yield in the filtrate was calculated to be 11.49 g (68.8% of theoretical yield). The remaining filtrate was once concentrated by nitrogen blowing to a concentration slightly higher than 30% solid content, and then a predetermined amount of MIBK was added to adjust the solid content concentration to 30% (hereinafter, this solution is referred to as solution C). Solution C was directly diluted with tetrahydrofuran to prepare a solution having a solid content weight concentration of 0.2%, and the solution was injected into gel permeation chromatography using tetrahydrofuran as a carrier solvent. 362
0, the weight average molecular weight was 7050, and the dispersity was 1.95. As a result of ²⁹ Si-nuclear magnetic resonance spectrum analysis, this dissolved component was confirmed to be a silicon resin having the following structural formula. [H (CH ₃ ) ₂ SiO _1/2 ] _0.35 (SiO _4/2 ) _1.0

Further, the solution C was dropped on a silicon wafer and left to stand at room temperature in the air to dry the solvent, thereby forming a film having a solid content of about 1 μm. Structural analysis of this film by a transmission mode using a Fourier transform infrared spectrophotometer revealed a broad strong absorption peak at 1100 cm ^{-1 due} to the siloxane bond, and a sharp strong absorption at 1260 cm ^{-1 due} to the Si-Me group. Peak, 9
10 cm ^-1 and from SiH groups 2150 cm ^-1 sharp strong absorption peaks, sharp weak absorption peak derived from the alkoxy group to 2870cm ^-1, 2960c
A sharp medium absorption peak derived from the m- ¹ attached C-H group was observed at 3500 cm- ¹ with a broad medium absorption peak derived from the silanol group.

[0028]

Example 1 The solution A prepared in Reference Example 1 was spin-coated on a semiconductor device substrate (step difference of 1.0 μm) to form a silicon resin film having a maximum thickness of 1.42 μm. After forming the film, this semiconductor device substrate is inserted into a cylindrical annular furnace,
It was heated in air at 400 ° C. for 1 hour, then gradually cooled in air and cooled to room temperature. When the characteristics of the ceramic silicon oxide film formed on the semiconductor device substrate were measured,
The maximum thickness was 1.22 μm, and the unevenness on the surface of the semiconductor device was uniformly flattened. As a result of microscopic observation, it was confirmed that this silicon oxide film had neither cracks nor pinholes. In addition, when structural analysis was performed by a transmission mode with a Fourier transform infrared spectrophotometer, the peaks of SiH groups in the silicon oxide film (910 cm ₋₁ and 2150
cm _-1), the peak of the silanol groups (3500 cm _-1 vicinity) and peak alkoxy groups (2870cm _-1) was confirmed to be lost completely any. Also,
It was confirmed that the obtained silicon oxide film was insoluble in organic solvents such as MIBK and acetone.

[0029]

Example 2 A silicon resin represented by the formula: [H (CH ₃ ) ₂ SiO _1/2 ] _0.5 (SiO _4/2 ) _1.0 , prepared in the same manner as in Reference Example 1, was dissolved in MIBK to obtain 30 wt. %
A solution was prepared. This solution was spin-coated on a semiconductor device substrate (step difference of 1.0 μm) to a maximum thickness of 1.54 μm.
m silicon resin film was formed. After forming the film, the semiconductor device substrate was inserted into a cylindrical annular furnace,
The mixture was heated at 0 ° C for 1 hour, then gradually cooled in air and cooled to room temperature. When the characteristics of the ceramic silicon oxide film formed on the semiconductor device substrate were measured, the maximum thickness was 1.
It was 38 μm, and the unevenness on the surface of the semiconductor device was uniformly flattened. As a result of microscopic observation, it was confirmed that this silicon oxide film had neither cracks nor pinholes. In addition, when a structural analysis was performed in a transmission mode with a Fourier transform infrared spectrophotometer, the Si in the silicon oxide film was analyzed.
H group peaks (910 cm _-1 and 2150 cm _-1 ),
It was confirmed that the silanol group peak (near 3500 cm ₋₁ ) and the alkoxy group peak (2870 cm ₋₁ ) were completely disappeared. Moreover, it was confirmed that the obtained silicon oxide film was insoluble in organic solvents such as MIBK and acetone.

[0030]

Example 3 The solution B prepared in Reference Example 2 was spin-coated on a semiconductor device substrate (step difference of 1.0 μm) to form a silicon resin film having a maximum thickness of 2.43 μm. After forming the film, this semiconductor device substrate is inserted into a cylindrical annular furnace,
It was heated in air at 400 ° C. for 1 hour, then gradually cooled in air and cooled to room temperature. When the characteristics of the ceramic silicon oxide film formed on the semiconductor device substrate were measured,
The maximum thickness was 1.98 μm, and the unevenness on the surface of the semiconductor device was uniformly flattened. As a result of microscopic observation, it was confirmed that this silicon oxide film had neither cracks nor pinholes. In addition, when structural analysis was performed by a transmission mode with a Fourier transform infrared spectrophotometer, the peaks of SiH groups in the silicon oxide film (910 cm ₋₁ and 2150
cm _-1), the peak of the silanol groups (3500 cm _-1 vicinity) and peak alkoxy groups (2870cm _-1) was confirmed to be lost completely any. Also,
It was confirmed that the obtained silicon oxide film was insoluble in organic solvents such as MIBK and acetone.

[0031]

Example 4 Solution C prepared in Reference Example 3 was spin-coated on a semiconductor device substrate (step difference of 1.0 μm) to form a silicon resin film having a maximum thickness of 1.72 μm. After forming the film, this semiconductor device substrate is inserted into a cylindrical annular furnace,
Heat in air at 300 ° C for 1 hour, then in air,
Heated at 400 ° C. for 1 hour. Then, it was gradually cooled in air and cooled to room temperature. When the characteristics of the ceramic silicon oxide film formed on the semiconductor device substrate were measured, the maximum thickness was 1.47 μm, and the unevenness on the surface of the semiconductor device was uniformly flattened. As a result of microscopic observation, it was confirmed that this silicon oxide film had neither cracks nor pinholes. In addition, when structural analysis was performed by a transmission mode with a Fourier transform infrared spectrophotometer, the peaks of SiH groups in the silicon oxide film (910 cm ₋₁ and 2150 c
m _-1 ), peak of silanol group (around 3500 cm _-1 )
It was confirmed that the peaks of the alkoxy group and the alkoxy group (2870 cm ₋₁ ) were completely disappeared. Moreover, it was confirmed that the obtained silicon oxide film was insoluble in organic solvents such as MIBK and acetone.

[0032]

[Comparative Example 1] Inorganic SOG (trade name: OCD-type II) manufactured by Tokyo Ohka Kogyo Co., Ltd. was spin-coated on a semiconductor device substrate (step difference of 1.0 μm) to a maximum thickness of 0.55 μm.
m resin coating was formed. After forming the film, the semiconductor device substrate was inserted into a cylindrical annular furnace, heated in air at 400 ° C. for 1 hour, and then gradually cooled in air and cooled to room temperature. An attempt was made to measure the characteristics of the silicon oxide film formed on the semiconductor device substrate, but many cracks that could be visually confirmed were generated, and the film thickness could not be measured.

[0033]

Comparative Example 2 Hydrogen silsesquioxane was dissolved in a MIBK solution to prepare a 30 wt% solution. This solution is spin-coated on a semiconductor device substrate (step difference of 1.0 μm),
A silicon resin film having a maximum thickness of 1.15 μm was formed. After forming the film, the semiconductor device substrate was inserted into a cylindrical annular furnace, heated in air at 400 ° C. for 1 hour, and then gradually cooled in air to room temperature. The maximum thickness of the silicon oxide film formed on the semiconductor device substrate was 0.98 μm, but it was confirmed by microscopic observation that many microcracks were generated in this silicon oxide film.

[0034]

The method for forming a silicon oxide film of the present invention is characterized in that a ceramic-like silicon oxide film insoluble in an organic solvent, which is a thick film and has neither cracks nor pinholes, can be formed on the surface of a substrate. Have.

Front Page Continuation (72) Inventor Satoru Mine 2-2 Chikusaigan, Ichihara, Chiba Toray Dow Corning Silicone Co., Ltd.

Claims (1)

[Claims] 1. The surface of the substrate has the general formula: (HR ₂ SiO _1/2 ) _X (SiO _4/2 ) _1.0 (wherein R is selected from the group consisting of hydrogen atom, alkyl group and aryl group). And X is 0.1 ≦ X ≦
It is 2.0. Forming a coating film comprising a silicon resin as a main component, and then heating the substrate having the coating film formed thereon to form a ceramic silicon oxide film. Method.